1. Field of the Invention
The present invention relates generally to battery charging. Particularly, the present invention relates to the sequential charging of batteries.
2. Description of the Related Art
Battery chargers that accept multiple batteries typically charge each battery at a high rate of charge. This requires the power circuits of the battery charger to be large enough to handle the power required to fast charge more than one battery.
Size and weight can be a consideration when a consumer decides to purchase a battery charger. For example, the consumer may want the charger for travel purposes and would therefore like the charger to be as small and light as possible. However, the multiple battery chargers are popular since consumers typically travel with more than one battery in order to have a fully charged battery ready when the other battery is discharged. There is a resulting need for a battery charger that has the capability for charging multiple batteries while maintaining a light weight and small size.
The present invention encompasses a process for sequentially charging a plurality of batteries in a battery charger. The high priority battery is first set by determining which battery was inserted first. The high priority battery is charged before any other battery. Once the high priority battery is charged, the next battery that was inserted is charged while power to the other batteries is removed.
In the preferred embodiment, one of the batteries is coupled to a mobile station, such as a phone. If the phone is in a call, the phone now has priority. In this case, power is removed from the other battery while the phone is powered. Once the call ends, priority passes back to the battery that had priority before the call was detected.